<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    *{
      padding: 0;
      margin: 0;
    }
    div{
      width: 500px; 
      height: 500px;
      border: 5px solid red;
      margin: 100px auto;
      position: relative;
    }
    p{
      width: 200px;
      height: 200px;
      background: #000;
      position: absolute;
      right: 0;
      bottom: 0;
    }
  </style>
</head>
<body>
  <section>
    <div>
      <p></p>
    </div>
</section>
</body>
</html>